Mobile communication networks such as cellular telephones and so forth, can detect the current location of mobile communication terminals. In recent years, several kinds of systems, which perform information providing services by using location information obtained by these types of mobile communication networks, are proposed.
For instance, in PHS (Personal Handy Phone System) networks, it is possible to detect, within the radio zone of which base station a mobile communication terminal currently exists; and the system for providing a location chase service by using this location information is known.
Also systems which use location information obtained by installing GPS (Global Positioning System) in mobile communication terminals are suggested.
Incidentally, expression formats of location information obtained on a mobile communication terminal differ according to the method adopted for location detection by the mobile communication terminal. For instance, in the above mentioned PHS network, the expression format is that of identification information (hereafter, referred to as the base station ID) for identifying the base station which administers the radio zone in which the mobile communication terminal is located; and in GPS, the expression of location information is in the latitude-longitude format obtained by measuring the location of the mobile communication terminal.
Also in computer systems, which provide various services by using location information, formats for expressing the requested location information differ.
For instance, a computer system may want to deal with location information expressed in the expression format of latitude-longitude, and alternatively, the computer system may want to deal with location information expressed in the format of a province.
As long as expression formats of location information vary depending on the mobile communication network or the computer system in use, it is not possible to provide a service which corresponds to the integration of various networks; a need which is about to develop rapidly.